public class DuckTest {
    public static void main(String[] args) {
        Duck mallard = new MallardDuck("绿色", 1.2);
        mallard.fly();
        mallard.quack();
        mallard.setHeavy(1.5);
        mallard.setHeavy(2);

        Duck peking = new PekingDuck("白色", 2.5);
        peking.fly();
        peking.quack();
        peking.setHeavy(3.0);
    }
}